﻿//
// (C) Copyright 2009 Irantha Suwandarathna (iranthas@hotmail.com)
// All rights reserved.
//

/* Copyright (c) 2001-2008, The HSQL Development Group
 * All rights reserved.
 *
 * Redistribution and use _in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * Redistributions of source code must retain the above copyright notice, this
 * list of conditions and the following disclaimer.
 *
 * Redistributions _in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer _in the documentation
 * and/or other materials provided with the distribution.
 *
 * Neither the name of the HSQL Development Group nor the names of its
 * contributors may be used to endorse or promote products derived from this
 * software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL HSQL DEVELOPMENT GROUP, HSQLDB.ORG,
 * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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 */

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using EffiProz.Core.Lib;
using EffiProz.Core.Store;
using EffiProz.Core.Errors;
using EffiProz.Core.Results;
using EffiProz.Core.Navigators;
using EffiProz.Core.DataTypes;

namespace EffiProz.Core.Persist
{
    public class LobStoreMem : LobStore
    {
        int lobBlockSize;
        int blocksInLargeBlock = 128;
        int largeBlockSize;
        EfzArrayList byteStoreList;

        public LobStoreMem(int lobBlockSize)
        {

            this.lobBlockSize = lobBlockSize;
            largeBlockSize = lobBlockSize * blocksInLargeBlock;
            byteStoreList = new EfzArrayList();
        }

        public byte[] getBlockBytes(int blockAddress, int blockCount)
        {

            byte[] dataBytes = new byte[blockCount * lobBlockSize];
            int dataBlockOffset = 0;

            while (blockCount > 0)
            {
                int largeBlockIndex = blockAddress / blocksInLargeBlock;
                byte[] largeBlock = (byte[])byteStoreList.get(largeBlockIndex);
                int blockOffset = blockAddress % blocksInLargeBlock;
                int currentBlockCount = blockCount;

                if ((blockOffset + currentBlockCount) > blocksInLargeBlock)
                {
                    currentBlockCount = blocksInLargeBlock - blockOffset;
                }

                Array.Copy(largeBlock, blockOffset * lobBlockSize,
                                 dataBytes, dataBlockOffset * lobBlockSize,
                                 currentBlockCount * lobBlockSize);

                blockAddress += currentBlockCount;
                dataBlockOffset += currentBlockCount;
                blockCount -= currentBlockCount;
            }

            return dataBytes;
        }

        public void setBlockBytes(byte[] dataBytes, int blockAddress,
                                  int blockCount)
        {

            int dataBlockOffset = 0;

            while (blockCount > 0)
            {
                int largeBlockIndex = blockAddress / blocksInLargeBlock;
                int largeBlockLimit = (blockAddress + blockCount)
                                      / blocksInLargeBlock;

                if ((blockAddress + blockCount) % blocksInLargeBlock != 0)
                {
                    largeBlockLimit++;
                }

                if (largeBlockIndex >= byteStoreList.size())
                {
                    byteStoreList.add(new byte[largeBlockSize]);
                }

                byte[] largeBlock = (byte[])byteStoreList.get(largeBlockIndex);
                int blockOffset = blockAddress % blocksInLargeBlock;
                int currentBlockCount = blockCount;

                if ((blockOffset + currentBlockCount) > blocksInLargeBlock)
                {
                    currentBlockCount = blocksInLargeBlock - blockOffset;
                }

                Array.Copy(dataBytes, dataBlockOffset * lobBlockSize,
                                 largeBlock, blockOffset * lobBlockSize,
                                 currentBlockCount * lobBlockSize);

                blockAddress += currentBlockCount;
                dataBlockOffset += currentBlockCount;
                blockCount -= currentBlockCount;
            }
        }

        public void close()
        {
            byteStoreList.clear();
        }
    }
}
